Parkinson's disease (PD) is pathologically characterized by selective degeneration of dopaminergic neurons in the midbrain and the presence of intracellular amyloidogenicα-synuclein (α-Syn) inclusions, known as Lewy bodies and Lewy neurites, which progress from the medulla to midbrain and throughout cortical areas. The gene discussed is SNCA; the disease is Parkinson disease.